mjhjmtu

My file contains

$Param_T=ABC49_SA_T2
$Param_V=ABC49BC_SA_V2
$Param_ST=ABC491_SA_M2

I am trying to replace a value starts with ABC*_ with XYZ12_

sed -i 's/ABC.*_/XYZ12_/g' INCR.parm

Above is the sed command i have used. It is not throwing any error but value is not changing.Could someone please help me with this ?

With sed, the way to implement non-greedy matching is to specify a set of character you don't want to match:

sed -i 's/=ABC[^_]*_/=XYZ12_/g' INCR.parm

That is: match "ABC" followed by zero or more non-underscore characters followed by underscore.

And note, you don't escape the dot. A "bare" dot means "match any character"; an escaped dot means "match a literal dot". You weren't making any replacements because none of the data matches the literal string "ABC."

Dont escape the "." that matches all characters [ Greedy]

sed -i 's/ABC.*_/XYZ12_/g' INCR.parm

Output:

$Param_T=XYZ12_T2
$Param_V=XYZ12_V2
$Param_ST=XYZ12_M2)

If you want to replace ABC* only uptill first underscore ( _ ) [Lazy], you need to use perl regex

use

perl -pe 's/ABC(.*?)_/XYZ12_/g' INCR.parm

Output:

$Param_T=XYZ12_SA_T2
$Param_V=XYZ12_SA_V2
$Param_ST=XYZ12_T2

'Greedy' means match longest possible string.

'Lazy' means match shortest possible string.